The level of blood oxygenation is of fundamental importance in establishing the health of both animals and humans. Often the successful analysis and treatment of a great many injuries and illnesses requires the constant surveillance of blood oxygenation level. One of the most popular and successful non-invasive techniques for measuring blood oxygenation levels is based on the knowledge that the magnitude of light passing through blood-perfused tissue is directly related to the level of blood oxygenation. Oximeters are devices that generate light in a non-invasive electro-optical sensor probe attached to a patient and measure light reflection or transmission during transillumination of the blood-perfused tissue of the patient's body part to which the sensor is attached.
Oximeter probes include a light source and photosensor in a malleable, flexible holder positioned in contact with the tissue at which the measurement is to be made, typically the thinnest available tissue section such as a fingertip, toe, hand or foot. In the past a variety of oximeter probes, both reusable and disposable, have been developed to allow engagement to these various body parts. However, these probes are cumbersome to attach, use and remove, are expensive, tend to break easily, do not accommodate a variety of appendage sizes, and allow enough probe movement with patient motion to introduce measurement errors called motion artifact errors.
One line of representative oximeter probes is made by Ohmeda of Louisville Colo. Ohmeda manufactures probes contained within a spring biased clip that is used to bias the probe into contact with a fingertip or toe. Other probes use elaborate patterns of tapes and adhesives to secure the probe to the tissue of interest. Hewlett-Packard Company of Palo Alto California manufactures the model HP M1190A Reusable Finger Transducer, a rubber capsule fitting over the fingertip.
Often times those patients whose conditions demand constant monitoring of blood oxygenation levels are the least able physically to withstand the rigors of presently employed sensor probe engagement devices and techniques. For example, burn and/or traumatized patients often cannot withstand the pressure of spring-biased clips on injured tissue, and find the time-consuming, laborious process of applying and removing securing tapes and adhesives excruciating at best and detrimental to their recovery. Occasionally the extreme pain of such a procedure to a patient may result in improper engagement of the probe by all but the most experienced health care professional. Moreover, as is often found in emergency situations, patients are diaphoretic or have oils or foreign substances on their tissue making it extremely difficult to use oximeter sensors secured by tape or adhesives.